1. Field of the Invention
The invention relates to a method for operating a drive with an internal combustion engine and an electric machine.
2. Description of the Prior art
DE 197 52 661 A1 describes an on-board power system for a motor vehicle with a combined drive including an electric machine and an internal combustion engine which act on the same drive train. On the one hand, the electric machine supports, for example, the starting process of the internal combustion engine as a motor and, on the other hand, outputs charge power to a vehicle operating battery, and possibly to an additional short-term starting capacitor, as a generator. In order to be able to operate with the highest possible efficiency and thus with the lowest possible loading of the energy stores or energy supply means in the generator operating mode, the electric losses both in the converter and in the asynchronous machine which is provided for the starter-generator are advantageously kept low. This is accomplished by virtue of the fact that, in a field-oriented control, the internal torque of the asynchronous machine of the start-generator is set according to the principle of controlling or regulating the rotor flow with optimum loss by correspondingly adapting the magnetizing current as a function of an active current which is determined in accordance with the respectively required drive torque.